CVE-1999-1382 in NetWare
Summary
by MITRE
NetWare NFS mode 1 and 2 implements the "Read Only" flag in Unix by changing the ownership of a file to root, which allows local users to gain root privileges by creating a setuid program and setting it to "Read Only," which NetWare-NFS changes to a setuid root program.
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Analysis
by VulDB Data Team • 10/20/2024
The vulnerability described in CVE-1999-1382 represents a critical privilege escalation flaw within Novell NetWare's NFS implementation, specifically affecting modes 1 and 2. This issue stems from a fundamental misimplementation of Unix file permissions and access control mechanisms within the network file system. The core problem lies in how NetWare NFS handles the "Read Only" attribute for files, creating an unintended pathway for local users to exploit system security controls.
The technical flaw manifests when NetWare NFS mode 1 or 2 encounters files marked with the "Read Only" flag in Unix environments. Instead of properly maintaining the intended read-only access restrictions, the system incorrectly interprets this flag and modifies file ownership to root. This misbehavior extends beyond simple permission changes, as the system actually transforms the file into a setuid root program when it processes the read-only flag. This transformation occurs because NetWare NFS implements a flawed mapping between its own attribute system and Unix permissions, where the read-only flag inadvertently triggers a setuid bit modification.
The operational impact of this vulnerability is severe and directly enables local privilege escalation attacks. An attacker with local access to a system running NetWare NFS in modes 1 or 2 can exploit this flaw by creating a setuid program and marking it as "Read Only." When NetWare NFS processes this file, it automatically converts the setuid bit to root ownership, effectively creating a persistent root privilege escalation mechanism. This vulnerability fundamentally undermines the principle of least privilege and allows attackers to gain system-level control without requiring authentication or network access. The attack vector is particularly dangerous because it requires only local system access and leverages the legitimate functionality of the NFS implementation to create malicious conditions.
This vulnerability aligns with CWE-276, which describes improper file permissions, and demonstrates a clear violation of the principle of least privilege in Unix-like systems. The flaw also relates to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation," as it provides a method for local users to elevate their privileges from standard user to root level. Additionally, this issue exemplifies the broader category of insecure file handling vulnerabilities where system components fail to properly validate or process file attributes, leading to unexpected security consequences. Organizations using NetWare NFS should immediately disable or upgrade their NFS implementations to avoid exploitation of this privilege escalation vulnerability.
The root cause of this vulnerability lies in the improper interpretation of file attributes within the NFS protocol implementation, where the system fails to distinguish between legitimate read-only access restrictions and security-sensitive setuid operations. This misconfiguration creates an unintended code execution pathway that bypasses normal Unix permission models and allows unauthorized privilege escalation. The vulnerability highlights the importance of proper access control implementation and the need for comprehensive testing of file attribute handling mechanisms in network file systems. System administrators should implement strict access controls and monitor for unauthorized setuid file creation, while also ensuring that legacy NetWare NFS implementations are either patched or replaced with more secure alternatives.